NASA Earth Observatory: Global warming
This easy to read introduction to global warming from NASA research scientists outlines the major points with great visuals and simple figures.
The National Centre for Atmospheric Research: Weather & Climate Basics
This website highlights the difference between weather and climate and walks you through the basic mechanics of climate change. This website shows you how the earth's climate has changed throughout time.
Need a quick and fast read on climate change? This is it. Nothing fancy here, just a good primer on the concepts and issues surrounding global warming.
I understand the basics, but I want to know more!
Exploratorium Global Climate Change
This website gives very detailed and well-referenced information about climate change and its effects on the atmosphere, the hydrosphere and the biosphere.
Pembina Institute: Climate Change
The Pembina Institute is a Canadian organization focused on promoting and advancing sustainable energy solutions within Canada. This site contains a lot of Canadian climate data and tips about how Canada can fight climate change.
The scientific facts of climate change
Climate Change 2001: The Scientific Basis
This comprehensive scientific assessment of climate change is published by the Intergovernmental Panel on Climate Change. This is not light reading, but provides a highly informative and unbiased presentation of the scientific basis for Global warming, with well referenced sources and detailed figures.
Want a slightly different perspective? This website is a supplement to a book on Global Warming by Spencer Weart that looks at the history global warming and climate change science. This site provides lots of information on climate data, theory, and some of the social impacts climate change in the US and around the world.